Metabolism of [4‐14C]Testosterone in the Rat Uterus in vitro

In view of the uterine action of androgens we have investigated in vitro the metabolism of [4-14C]-testosterone in uterine tissue of ovariectomized rats. After purification of the extracts on Amberlite XAD-2 the metabolites have been isolated by gel column chromatography on Sephadex LH-20, and over-run thin-layer chromatography on silica gel. Five metabolites were isolated and identified during these incubation studies: 4-androstene-3,17-dione, 17β-hydroxy-5α-androstan-3-one, 5α-androstane-3α, 17β-diol, 4-androstene-3β, 17β-diol and 4-androstene-3α,17β-diol. Furthermore, two polar C19O3-metabolites and one isopolar to 5α-androstane-3,17-dione have also been detected. The metabolites were characterized by radioactive gas chromatography, and determination of the relative specific activity in the eluates of Sephadex column chromatography. The identification of allylic alcohols was complemented by their oxidation to 4-androstene-3,17-dione. The present data show that activity of 17β,3α- and 3β-hydroxysteroid-oxidoreductase and 5α-ring-reductase are involved in the metabolism of testosterone in vitro in the rat uterus. The very low 5α-reductase activity under the experimental conditions used in this work explains the formation of allylalcohols as the principal metabolites of testosterone in the rat uterus.